The arch rises a few steps away from Piazza del Mercato, the ancient Roman forum, of which it was the triumphal entrance. The inscription still visible on the front informs that it was erected on the initiative of the senate of Spoleto in the year 23 A.D., in honour of the princes Drusus and Germanicus, respectively son and adopted son of the emperor Tiberius. The arch has only one fornix and is composed of large square blocks of stone, while the decorations are now very fragmentary. Starting from the Middle Ages, it was incorporated into the nearby buildings, so that the western pier is still not visible today, while the eastern one has been brought to light up to the ancient laying surface, related to the paving of the cardo maximus.
